An assessment of PWR steam generator condensation at the Oregon State University APEX facility

This report describes the testing to assess steam generator U-tube steam condensation conducted at the Oregon State University Advanced Plant Experiment Test Facility from 2005 to 2007. Six separate SG condensation (without non-condensable gas) tests were conducted as part of this test program. These tests were designed to evaluate steam condensation rates in a scaled Pressurized Water Reactor steam generator at various primary and secondary side pressures and inlet steam mass flow rates. The experimental data will provide a basis to assess TRACE steam generator modeling techniques and to assist in development of improved models for condensation and steam generator thermal-hydraulics.     

Guest Editors’ introduction to special section: Supply chain trading agent research

Predictability of prices and availability are becoming less predictable in emerging supply chain environments, as product lifecycles shorten and organizations pursue increased agility. This leads to new competitive and strategic interactions among actors across the supply chain. It also threatens to overwhelm human decision capabilities with a combinatorial explosion of possibilities. Recent advances in technical infrastructure have enabled new types of interorganizational interactions, but have not addressed the need for fundamentally new kinds of decision support systems that can help tame the complexity of this emerging environment. The papers in this special issue describe progress in semi-autonomous trading agents that are being developed to meet this need.     

An Integrating Wide Dynamic-Range Image Sensor With a Logarithmic Response

An integrating CMOS image sensor with a wide dynamic range is described. The dynamic range of these pixels is controlled by a user-defined reference voltage that creates a photocurrent-dependent effective integration time. The operation of these pixels and a method of obtaining a well-controlled logarithmic response are both described. Furthermore, described are the results of two alternative methods of correcting the fixed pattern noise in these pixels and measurements of the temporal noise from individual pixels. These results show that with these pixels, it is possible to match the contrast sensitivity of the human visual system.     

The use of aqueous alkaline hydrolysis to reveal the fine structure of poly(ethylene terephthalate) fibers

The fine structure and physical properties of bright and semidull poly(ethylene terephthalate) (PET) fibers were investigated as successive layers of the polymer were removed by hydrolysis using aqueous solutions of sodium hydroxide up to weight losses of 90 and 68%, respectively. For both types large changes in molecular weight distribution did not occur, although as weight loss increased, the density of the remaining fiber increased. Alterations in fine structure with weight loss were also observed by thermal analysis. Greater strength loss with decreasing weight occurred for the semidull fiber than for the bright sample. Larger pits formed on the surface of the hydrolyzed semidull fibers than on the surface of the bright products. This observation is attributed to the titanium oxide present in the semidull fibers. It was also noted that as the density of the bright PET samples was increased by heatsetting, the rate of hydrolysis decreased.     

Community Participation in Urban Planning: the Case of Managing Green Spaces in Kumasi,Ghana

The entrenched position now taken by participatory planning in urban planning practice has made the call for community participation in the planning process now higher than ever. Community participation has been well-acknowledged to give local people a voice in planning decisions. This paper assessed the level of participation by local people in the management of urban green spaces. Using a case study research approach, Kumasi city, once the garden city of Africa was selected as the study area. The Kumasi city authorities, and residents including opinion leaders, and officials of allied bodies on green spaces constituted the study’s target population. A blend of qualitative research techniques such as in-depth interviews, focus group discussion, and personal observation was employed whilst theoretical sampling technique was adopted. It was found out that the participation of the local people in the management of green space was low. The local people were neither consulted nor informed on green space projects (parks and gardens) by the city authorities. They were also not empowered to self-facilitate initiatives on green spaces and passively involved in final decisions on green spaces. To correct the situation, it is recommended that features of the communicative planning theory such as dialogue, consensus building, and facilitative leadership should be given attention in the urban planning system of Kumasi especially on green space projects.     

Stakeholder engagement in water governance as social learning: lessons from practice

ABSTRACT

The OECD Principles on Water Governance set out various requirements for stakeholder engagement. Coupled with conceptualizations of social learning, this article asks how we define and enact stakeholder engagement and explores the actual practice of engagement of stakeholders in three fields of water governance. The results suggest that a key consideration is the purpose of the stakeholder engagement, requiring consideration of its ethics, process, roles and expected outcomes. While facilitators cannot be held accountable if stakeholder engagement ‘fails’ in terms of social learning, they are responsible for ensuring that the enabling conditions for social learning are met.     

The effect of competitive adsorption on the rate of diffusion

Evidence is presented that the apparent diffusion coefficient of one penetrant can be increased by competition from another penetrant for the same adsorption sites in polyester. The competition is governed by the relative diffusivities of the penetrants and their affinities for the adsorption sites.     

Carbon molecular sieve films produced by dc sputtering

This paper reports adsorption measurements that show molecular sieve effects in amorphous hydrogenated carbon (a-C : H) films deposited by d.c. magnetron discharge decomposition of acetylene. Adsorption of organic gases on the films is studied by using a quartz crystal microbalance technique. The sieve effect in this material depends on both deposition and annealing conditions. Films having significant molecular sieve effects are found to be typically microporous and to have a very small characteristic micropore dimension. It is suggested that the d.c. sputtered a-C : H film may be useful as a molecular sieve material in selective adsorption and gas permeation studies.     

Flexure of thin rigid contact lenses.

The flexure of spherical rigid contact lenses was measured on the eyes of 10 young subjects using a videokeratoscope. Five subjects had little or no with-the-rule astigmatism (<0.75 D) andfive had moderate levels of with-the-rule astigmatism (1.00-2.00 D). Two lens materials (polymethylmethacrylate [PMMA] and Boston XO) in three centre thicknesses (0.05, 0.10 and 0.15 mm) were used in the study. No significant difference in the amount of flexure was found between the two materials tested. The degree of regular astigmatism on the lens front surface was found to increase as the centre thickness of the contact lens decreased. For the astigmatic group, the lenses with centre thicknesses of 0.05 mm had levels of front surface astigmatism similar to those of the underlying cornea. On spherical corneas the level of regular astigmatism can exceed that of the cornea for thinner lenses. When sphero-cylinder variations are accounted for, residual higher order aberration (root mean square) levels were found to approach those of the cornea when the lens thickness was reduced to 0.05 mm.     

Measurements of chemical warfare agent degradation products using an electrophoresis microchip with contactless conductivity detector

This paper reports on a microfluidic device for the screening of organophosphonate nerve agent degradation products. The miniaturized system relies on an efficient chip-based separation of alkyl methylphosphonic acids (breakdown products of Sarin, Soman, and VX nerve agents) followed by their sensitive contactless conductivity detection. Experimental parameters relevant to the separation and detection processes have been optimized to yield high sensitivity (with 48-86 microg L(-1) detection limits), fast response (50 s for a three alkyl methylphosphonic acid mixture), high precision (RSD = 3.8-5.0%), and good linearity (over the 0.3-100 mg L(-1) range). Applicability to natural (river) water samples is demonstrated. The new microsystem offers promise for monitoring degradation products of chemical warfare agents, with advantages of speed/warning, efficiency, portability, sample size, and cost compared to conventional ion chromatography or capillary electrophoresis systems.